Super Door Stop Alarm & Warning Decal Set Powerful 118 dB alarm with on-off switch. Compact and lightweight - Great for travel. Wedge-shaped design and non-skid pad on the bottom of unit prevent door from opening Adjustable sensitivity switch prevents tampering. No installation required. Set includes a highly visible & repositionable vinyl security warning decal for windows. Wedge-shaped design and non-skid pad on the bottom of unit prevent door from opening